From 5fb1b8a1630115f3aa3cd6bb7bc9ba5122867f66 Mon Sep 17 00:00:00 2001

From: Dan Williams <dan.j.williams@intel.com>

Date: Sun, 23 Jan 2022 16:54:39 -0800

Subject: [PATCH 118/217] cxl/list: Use 'physical_node' for root port

 attachment detection

Platform firmware objects like ACPI0016 link from /sys/bus/acpi to

/sys/bus/pci via a 'physical_node' attribute. Consider that link when

attempting to link memdevs to root ports.

Emit it in the the target listing as the 'alias' for the listed target

device.

Link: https://lore.kernel.org/r/164298567943.3021641.12696733268157328279.stgit@dwillia2-desk3.amr.corp.intel.com

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>

---

 Documentation/cxl/lib/libcxl.txt |  6 ++++++

 cxl/json.c                       |  8 ++++++++

 cxl/lib/libcxl.c                 | 16 +++++++++++++++-

 cxl/lib/libcxl.sym               |  1 +

 cxl/lib/private.h                |  1 +

 cxl/libcxl.h                     |  1 +

 6 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/Documentation/cxl/lib/libcxl.txt b/Documentation/cxl/lib/libcxl.txt

index bd92fef..a68a58b 100644

--- a/Documentation/cxl/lib/libcxl.txt

+++ b/Documentation/cxl/lib/libcxl.txt

@@ -389,6 +389,7 @@ unsigned long cxl_target_get_id(struct cxl_target *target);

 const char *cxl_target_get_devname(struct cxl_target *target);

 bool cxl_target_maps_memdev(struct cxl_target *target,

                            struct cxl_memdev *memdev);

+const char *cxl_target_get_physical_node(struct cxl_target *target);

 ----

 The position of a decoder along with the interleave granularity dictate

 which address in the decoder's resource range map to which port.

@@ -410,6 +411,11 @@ The cxl_target_maps_memdev() helper is the companion of

 cxl_decoder_get_target_by_memdev() to determine which downstream ports /

 targets are capable of mapping which memdevs.

+Some platform firmware implementations define an alias / companion

+device to represent the root of a PCI device hierarchy. The

+cxl_target_get_physical_node() helper returns the device name of that

+companion object in the PCI hierarchy.

+

 include::../../copyright.txt[]

 SEE ALSO

diff --git a/cxl/json.c b/cxl/json.c

index 3a37909..d81aed8 100644

--- a/cxl/json.c

+++ b/cxl/json.c

@@ -342,6 +342,7 @@ struct json_object *util_cxl_decoder_to_json(struct cxl_decoder *decoder,

 	cxl_target_foreach(decoder, target) {

 		struct json_object *jtarget = json_object_new_object();

+		const char *phys_node;

 		if (!jtarget)

 			continue;

@@ -351,6 +352,13 @@ struct json_object *util_cxl_decoder_to_json(struct cxl_decoder *decoder,

 		if (jobj)

 			json_object_object_add(jtarget, "target", jobj);

+		phys_node = cxl_target_get_physical_node(target);

+		if (phys_node) {

+			jobj = json_object_new_string(phys_node);

+			if (jobj)

+				json_object_object_add(jtarget, "alias", jobj);

+		}

+

 		val = cxl_target_get_position(target);

 		jobj = json_object_new_int(val);

 		if (jobj)

diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c

index 877f42c..7bf7949 100644

--- a/cxl/lib/libcxl.c

+++ b/cxl/lib/libcxl.c

@@ -72,6 +72,7 @@ static void free_target(struct cxl_target *target, struct list_head *head)

 	if (head)

 		list_del_from(head, &target->list);

 	free(target->dev_path);

+	free(target->phys_path);

 	free(target);

 }

@@ -970,7 +971,11 @@ static void *add_cxl_decoder(void *parent, int id, const char *cxldecoder_base)

 			free(target);

 			break;

 		}

-		dbg(ctx, "%s: target%ld %s\n", devname, i, target->dev_path);

+		sprintf(port->dev_buf, "%s/dport%d/physical_node", port->dev_path, did);

+		target->phys_path = realpath(port->dev_buf, NULL);

+		dbg(ctx, "%s: target%ld %s phys_path: %s\n", devname, i,

+		    target->dev_path,

+		    target->phys_path ? target->phys_path : "none");

 		list_add(&decoder->targets, &target->list);

 	}

@@ -1138,9 +1143,18 @@ CXL_EXPORT bool cxl_target_maps_memdev(struct cxl_target *target,

 	dbg(ctx, "memdev: %s target: %s\n", memdev->host_path,

 	    target->dev_path);

+	if (target->phys_path)

+		return !!strstr(memdev->host_path, target->phys_path);

 	return !!strstr(memdev->host_path, target->dev_path);

 }

+CXL_EXPORT const char *cxl_target_get_physical_node(struct cxl_target *target)

+{

+	if (!target->phys_path)

+		return NULL;

+	return devpath_to_devname(target->phys_path);

+}

+

 CXL_EXPORT struct cxl_target *

 cxl_decoder_get_target_by_memdev(struct cxl_decoder *decoder,

 				 struct cxl_memdev *memdev)

diff --git a/cxl/lib/libcxl.sym b/cxl/lib/libcxl.sym

index cb33180..ce01298 100644

--- a/cxl/lib/libcxl.sym

+++ b/cxl/lib/libcxl.sym

@@ -141,4 +141,5 @@ global:

 	cxl_target_get_id;

 	cxl_target_get_devname;

 	cxl_target_maps_memdev;

+	cxl_target_get_physical_node;

 } LIBCXL_1;

diff --git a/cxl/lib/private.h b/cxl/lib/private.h

index 1743a24..7e7742d 100644

--- a/cxl/lib/private.h

+++ b/cxl/lib/private.h

@@ -77,6 +77,7 @@ struct cxl_target {

 	struct list_node list;

 	struct cxl_decoder *decoder;

 	char *dev_path;

+	char *phys_path;

 	int id, position;

 };

diff --git a/cxl/libcxl.h b/cxl/libcxl.h

index abda0e5..0e484cc 100644

--- a/cxl/libcxl.h

+++ b/cxl/libcxl.h

@@ -140,6 +140,7 @@ unsigned long cxl_target_get_id(struct cxl_target *target);

 const char *cxl_target_get_devname(struct cxl_target *target);

 bool cxl_target_maps_memdev(struct cxl_target *target,

 			    struct cxl_memdev *memdev);

+const char *cxl_target_get_physical_node(struct cxl_target *target);

 #define cxl_target_foreach(decoder, target)                                    \

 	for (target = cxl_target_get_first(decoder); target != NULL;           \

-- 

2.27.0